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Anatomy of the Lumbopelvic Spine

Superior View

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Lateral View

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Anterior View

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Posterior View

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Physiologic (Osteokinematic) Motions of Lumbopelvic Spine

Operant Definitions

  • Iliosacral (I/S) motion: Motion of ilium in reference to sacrum

  • Sacroilial (S/I) motion: Motion of sacrum in reference to ilium

    • Reference for lumbar motion is superior vertebra of motion segment

    • Reference for I/S motion is ASIS

    • Reference for S/I motion is anterior base of sacrum

  • I/S anterior/posterior ROT (tilt): Motion of ASIS anterior/inferior & posterior/superior in sagittal plane

  • I/S inflare/outflare: Motion of ASIS medially & laterally in transverse plane

  • I/S upslip/downslip: Motion of ASIS superiorly & inferiorly in frontal plane

  • S/I flexion/extension (nutation/counternutation): Motion of sacral base anterior & posterior in sagittal plane

  • S/I SB: Motion of sacral base in frontal plane

  • S/I ROT: Motion of sacral base in transverse plane

  • S/I forward/backward torsion: Triplanar motion of sacral sulcus anteriorly & posteriorly about an oblique axis

Coupled/Combined Motion

  • Lumbar SB & ROT occur contralaterally in neutral

  • Lumbar SB & ROT occur ipsilaterally out of neutral

  • Hip motion coupled with ilial (I/S) motion

  • Lumbar motion coupled with sacral (S/I) motion

  • Lumbar segmental maximal facet opening (R) occurs with FB, SB (L), ROT (R)

  • Lumbar segmental maximal facet closing (R) occurs with BB, SB (R), ROT (L)

Coupled Joint Motions

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Motion Innominate (I/S) Sacrum (S/I)
Hip flex Ipsilateral posterior ROT Ø
Hip ext Ipsilateral anterior ROT Ø
Hip IR Ipsilateral inflare Ø
Hip ER Ipsilateral outflare Ø
Lumbar FB Anterior ROT Ext, then flex
Lumbar BB Posterior ROT Flex, then ext
Lumbar ROT Ipsilateral posterior ROT & contralateral anterior ROT Ipsilateral ROT
Lumbar SB Ipsilateral anterior ROT & contralateral posterior ROT Ipsilateral SB

Physiologic (Osteokinematic) Motions of the Lumbopelvic Spine

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Joint Normal ROM OPP CPP Normal End Feel(s) Capsular Pattern

FB = 40°–60°

BB = 20°–35°

SB = 15°–20°

ROT = 3°–18°

FB, contralateral SB, & ipsilateral ROT BB, ipsilateral SB, & contralateral ROT Elastic Limited in FB, contralateral SB, & ipsilateral ROT

S/I & I/S

Angular motion = 3°–20°

Translatory motion = 0.5–8.0 mm

Triplanar 5°–8°

Max hip ER Max hip IR    

Accessory (Arthrokinematic) Motions of the Lumbopelvic Spine

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  Arthrology Arthrokinematics
Lumbar Primarily sagittal plane orientation with superior facets of inferior vertebra facing medially & inferior facets of superior vertebra facing laterally


  • Inferior facet of superior vertebra glides up & forward on superior facet of inferior vertebra

  • Nucleus pulposus migrates ...

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